U.S. patent application number 11/988472 was filed with the patent office on 2009-05-28 for active energy ray-curable resin composition for plastic films, and plastic labels.
This patent application is currently assigned to FUJI SEAL INTERNATIONAL INC.. Invention is credited to Suguru Arai, Hidenori Dobashi, Akira Miyazaki, Akira Shintani.
Application Number | 20090136759 11/988472 |
Document ID | / |
Family ID | 37637193 |
Filed Date | 2009-05-28 |
United States Patent
Application |
20090136759 |
Kind Code |
A1 |
Shintani; Akira ; et
al. |
May 28, 2009 |
Active Energy Ray-Curable Resin Composition for Plastic Films, and
Plastic Labels
Abstract
Disclosed is an active energy ray-curable resin the composition
for plastic films which contains an oxetane compound, an epoxy
compound, and at least one silicone compound selected from
epoxy-modified silicones, fluorine-modified silicones,
amino-modified silicones, (meth)acrylic-modified silicones, and
polyether-modified silicones. The resin the composition has
excellent printability such as gravure printability and
flexographic printability and cures rapidly to attain high
productivity. After curing, it gives a cured layer which excels in
adhesion to the plastic base film and in toughness and has good
recoatability. A plastic label using the resin the composition
excels in surface scratch resistance and crumpling resistance. This
label is hence useful especially as a label to be applied to
plastic containers, metallic containers such as bottle cans.
Inventors: |
Shintani; Akira; (Mie,
JP) ; Miyazaki; Akira; (Mie, JP) ; Arai;
Suguru; (Mie, JP) ; Dobashi; Hidenori; (Mie,
JP) |
Correspondence
Address: |
EDWARDS ANGELL PALMER & DODGE LLP
P.O. BOX 55874
BOSTON
MA
02205
US
|
Assignee: |
FUJI SEAL INTERNATIONAL
INC.
Osaka-shi
JP
|
Family ID: |
37637193 |
Appl. No.: |
11/988472 |
Filed: |
July 12, 2006 |
PCT Filed: |
July 12, 2006 |
PCT NO: |
PCT/JP2006/313893 |
371 Date: |
January 8, 2008 |
Current U.S.
Class: |
428/413 ;
525/418; 525/474 |
Current CPC
Class: |
C08G 59/306 20130101;
C09D 163/00 20130101; C08G 65/18 20130101; Y10T 428/31511 20150401;
C08L 63/00 20130101; G03F 7/0757 20130101; C09D 11/101
20130101 |
Class at
Publication: |
428/413 ;
525/418; 525/474 |
International
Class: |
B32B 27/00 20060101
B32B027/00; B32B 27/38 20060101 B32B027/38; C08L 67/06 20060101
C08L067/06; C08L 83/02 20060101 C08L083/02 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 13, 2005 |
JP |
2005-204435 |
Jun 13, 2006 |
JP |
2006-163819 |
Claims
1. Active energy ray-curable resin composition for a plastic film,
comprising an oxetane compound, an epoxy compound, and at least one
silicone compound selected from the group consisting of
epoxy-modified silicones, fluorine-modified silicones,
amino-modified silicones, (meth)acrylic-modified silicones, and
polyether-modified silicones.
2. Active energy ray-curable resin composition for a plastic film,
according to claim 1, wherein the resin composition comprises the
oxetane compound and the epoxy compound in a weight ratio of 2:8 to
8:2 and comprises 0.1 to 40 parts by weight of the silicone
compound to 100 parts by weight of a total amount of the oxetane
compound and the epoxy compound.
3. Active energy ray-curable resin composition for a plastic film,
according to claim 1, comprising 10 to 75 percent by weight of the
oxetane compound, 5 to 35 percent by weight of the epoxy compound,
and 0.1 to 20 percent by weight of the epoxy-modified silicone.
4. A plastic label comprising the plastic film and a coating
arranged on at least one side of the plastic film, wherein the
coating is comprised of the active energy ray-curable resin
composition for the plastic film of claim 1.
5. Active energy ray-curable resin composition for a plastic film,
according to claim 1, wherein the plastic film is a shrink
film.
6. A plastic label according to claim 4, wherein the plastic label
is a shrink label with the plastic film being a shrink film.
7. Active energy ray-curable resin composition for a plastic film,
according to claim 2, comprising 10 to 75 percent by weight of the
oxetane compound, 5 to 35 percent by weight of the epoxy compound,
and 0.1 to 20 percent by weight of the epoxy-modified silicone.
8. A plastic label comprising the plastic film and a coating
arranged on at least one side of the plastic film, wherein the
coating is comprised of the active energy ray-curable resin
composition for the plastic film of claim 2.
9. A plastic label comprising the plastic film and a coating
arranged on at least one side of the plastic film, wherein the
coating is comprised of the active energy ray-curable resin
composition for the plastic film of claim 3.
10. A plastic label comprising the plastic film and a coating
arranged on at least one side of the plastic film, wherein the
coating is comprised of the active energy ray-curable resin
composition for the plastic film of claim 7.
11. Active energy ray-curable resin composition for a plastic film,
according to claim 2, wherein the plastic film is a shrink
film.
12. Active energy ray-curable resin composition for a plastic film,
according to claim 3, wherein the plastic film is a shrink
film.
13. Active energy ray-curable resin composition for a plastic film,
according to claim 7, wherein the plastic film is a shrink
film.
14. A plastic label according to claim 8, wherein the plastic label
is a shrink label with the plastic film being a shrink film.
15. A plastic label according to claim 9, wherein the plastic label
is a shrink label with the plastic film being a shrink film.
16. A plastic label according to claim 10, wherein the plastic
label is a shrink label with the plastic film being a shrink film.
Description
TECHNICAL FIELD
[0001] The present invention relates to the active energy
ray-curable resin composition to be applied to a plastic film, and
a plastic label containing a plastic film and the resin composition
applied to the plastic film.
BACKGROUND ART
[0002] As containers for beverages such as tea beverages and soft
drinks, widely used are plastic bottles such as polyethylene
terephthalate (PET) bottles; and metallic bottles such as bottle
cans. Labels such as so-called shrink labels and orientation labels
are often attached to these containers. Such labels are used to
indicate descriptions about contents and to impart functionalities
such as decorativeness, scratch resistance, and slipperiness. The
labels are composed of plastic films coated with the resin
composition. The resin composition includes, for example, the
coating composition such as inks.
[0003] These resin composition should have processability suitable
for their respective label processing, and, after coating and
curing, the resin composition should give resin layers (hereinafter
also referred to as "cured layer(s)") that have such toughness as
to inhibit decrease in decorativeness and functionalities due to
scratch during the course of distribution of commercial products
with labels. In particular, currently-used containers for beverages
are often complicatedly and sophisticatedly three-dimensionally
molded containers. Accordingly, requirements on processability of
films, particularly shrink films, to be attached to these
containers have more and more increased. For example, such films
should satisfactorily follow such complicated shapes of containers.
For ensuring these high processability and high toughness
simultaneously, it is necessary for cured layers to have high
adhesion to base films.
[0004] To apply the resin composition typically as printing inks to
bases, gravure printing is generally employed. However, gravure
inks generally contain large amounts of organic solvents, and these
solvents must be removed by vaporization in production processes.
The recovery and decomposition of these solvents are likely to be
made mandatory from the viewpoint of reducing loads on the
environment. Spending on new plants and equipment for the recovery
and decomposition of the solvents and cost for their maintenance
have therefore become new loads on the gravure printing industry.
In contrast, water-based inks use no organic solvent or only small
amounts of organic solvents. However, these water-based inks suffer
from a low printing speed which inevitably leads to low
productivity, because the water-based inks are dried more slowly
than solvent-based gravure inks.
[0005] Under these circumstances, the coating composition
containing epoxy compounds as base materials and using
substantially no solvent has been developed. Among them, the energy
ray-curable composition containing a mixture of an epoxy compound
and an oxetane compound is known as the coating composition in
which flexibility is imparted to a relatively fragile epoxy resin
(for example, Patent Document 1). In the technique disclosed in
Patent Document 1, only basic properties such as viscosity of the
composition and tensile strength of the cured composition are
considered, but properties in practical use, such as coatability
(printability) to plastic films and curability thereon, are not
considered.
[0006] As the coating composition for use as an ink, there is known
the active energy ray-curable ink composition which contains a
compound having an oxetane ring, a photoinitiator, and a pigment
and further contains a compound having an epoxy group, a compound
having a vinyl-ether group, and/or a compound having a
(meth)acryloyl group (for example, Patent Document 2). The
technique disclosed in Patent Document 2 still suffers from
unsolved problems such that the composition does not cure
sufficiently rapidly to be used in high-speed gravure printing or
flexographic printing. In addition, no consideration is made on
recoatability and on changes in properties upon shrinking
process.
[0007] Patent Document 1: Japanese Unexamined Patent Application
Publication (JP-A) No. H11-140279
[0008] Patent Document 2: Japanese Unexamined Patent Application
Publication (JP-A) No. H08-143806.
DISCLOSURE OF THE INVENTION
Problems to be Solved by the Invention
[0009] An object of the present invention is to provide the active
energy ray-curable resin composition, to be applied to a plastic
film, which is the resin composition containing substantially no
solvent, has excellent printability (coatability) and cures
satisfactorily when used typically in gravure printing to thereby
attain good productivity. After coating and curing, the composition
gives a cured layer that excels typically in adhesion to the
plastic film, toughness, recoatability, and following capability
typically upon shrinking process. Another object of the present
invention is to provide a plastic label which includes a plastic
film coated with the active energy ray-curable resin composition
applied on the plastic film and excels typically in surface scratch
resistance and crumpling resistance.
Means for Solving the Problems
[0010] After intensive investigations to achieve the objects, the
present inventors have found that the resin composition having
excellent properties can be obtained by compounding at least three
components of an oxetane compound, an epoxy compound, and a
specific silicone compound. Specifically, this resin composition
has dramatically improved coatability, adhesion, and cure rate to
attain excellent productivity, and, after coating and curing, gives
a cured layer that excels in properties such as processability and
scratch resistance. They have also found that a plastic label
having these excellent properties can be obtained with the resin
composition. The present invention has been made based on these
findings.
[0011] Specifically, the present invention provides the active
energy ray-curable resin composition for a plastic film. The
composition contains an oxetane compound, an epoxy compound, and at
least one silicone compound selected from the group consisting of
epoxy-modified silicones, fluorine-modified silicones,
amino-modified silicones, (meth)acrylic-modified silicones, and
polyether-modified silicones.
[0012] In the present invention, the active energy ray-curable
resin composition for a plastic film may contain the oxetane
compound and the epoxy compound in a weight ratio of 2:8 to 8:2 and
contain 0.1 to 40 parts by weight of the silicone compound to 100
parts by weight of the total amount of the oxetane compound and the
epoxy compound.
[0013] In the present invention, the active energy ray-curable
resin composition for a plastic film may contain 10 to 75 percent
by weight of an oxetane compound, 5 to 35 percent by weight of an
epoxy compound, and 0.1 to 20 percent by weight of an
epoxy-modified silicone.
[0014] In the present invention, a plastic label may include a
plastic film and a coating arranged on at least one side of the
plastic film, in which the coating is comprised of the active
energy ray-curable resin composition for a plastic film.
[0015] In the active energy ray-curable resin composition for a
plastic film of the present invention, the plastic film may be a
shrink film.
[0016] The plastic label of the present invention may be a shrink
label, in which the plastic film is a shrink film.
ADVANTAGES
[0017] The active energy ray-curable resin composition for plastic
films according to the present invention has a low viscosity and
can thereby be satisfactorily applied to a plastic film typically
through gravure printing or flexographic printing. They also cure
rapidly, to attain higher productive efficiency of plastic labels.
Because the resin composition satisfactorily adheres to plastic
films, after curing, it gives cured layers that can satisfactorily
follow the deformation of base films during shrinking process and
excels in scratch resistance and crumpling resistance. In addition,
it excels in resistance to chemicals and adhesion to another ink
composition overcoated thereon (recoatability). Accordingly, the
resin composition of the present invention is especially useful
typically as printing inks for plastic labels. The plastic labels
applied with the resin composition are especially useful as labels
to be applied to glass bottles, plastic containers such as PET
bottles, and metallic containers such as bottle cans.
BEST MODE FOR CARRYING OUT THE INVENTION
[0018] The active energy ray-curable resin composition for plastic
films according to the present invention (hereinafter simply
referred to as "the resin composition") will be illustrated in
detail below.
[0019] The resin composition according to the present invention is
the active energy ray-curable composition that can be cured by the
action of active energy rays such as visible rays, ultraviolet
rays, and electron beams. In contrast to thermosetting resin
composition, the active energy ray-curable resin composition can be
suitably applied to shrink films and other bases (substrates) that
are likely to deform due to heat. Of such active energy rays, the
resin composition is preferably curable by the action of
ultraviolet rays or near-ultraviolet rays. They may absorb rays at
wavelengths of preferably 200 to 460 nm and more preferably 300 to
460 nm.
[0020] The resin composition according to the present invention
contains an oxetane compound (hereinafter referred to as "Component
A"), an epoxy compound (hereinafter referred to as "Component B"),
and at least one silicone compound (hereinafter referred to as
"Component C") selected from the group consisting of epoxy-modified
silicones (silicones having epoxy group), fluorine-modified
silicones, amino-modified silicones, (meth)acrylic-modified
silicones, and polyether-modified silicones, as essential
components. Advantages of the present invention may not be obtained
when the composition does not contain the above-mentioned three
components. The term "(meth)acrylic" as used herein indicates
"acrylic" and/or "methacrylic". Silicones containing oxetanyl group
and/or epoxy group are not included in Components A and B
herein.
[0021] The resin composition according to the present invention
preferably contains a polymerization initiator for exhibiting
curability with active energy rays (hereinafter referred to as
"photoinitiator"), in addition to the three components. To have
other functions, they may further contain any other components such
as other polymer composition, pigments, sensitizers, dispersing
agents, antioxidants, flavors, deodorants, stabilizers, lubricants,
and segregation inhibitors within ranges not adversely affecting
advantages of the present invention:
[0022] Component A for use in the present invention is a compound
having at least one oxetanyl group per molecule and can be any of
monomers and oligomers. Oxetane compounds described in, for
example, Japanese Unexamined Patent Application Publication (JP-A)
No. H08-85775 and Japanese Unexamined Patent Application
Publication (JP-A) No. H08-134405 can be used, of which compounds
having one or two oxetanyl groups per one molecule are preferred.
Examples of compounds having one oxetanyl group per one molecule
include 3-ethyl-3-[(phenoxy)methyl]oxetane,
3-ethyl-3-(hexyloxymethyl)oxetane,
3-ethyl-3-(2-ethylhexyloxymethyl)oxetane,
3-ethyl-3-(hydroxymethyl)oxetane, 3-ethyl-3-(chloromethyl)oxetane,
and 3-ethyl-3-(cyclohexyloxymethyl)oxetane. Examples of compounds
having two oxetanyl groups per one molecule include
1,4-bis[[(3-ethyloxetan-3-yl)methoxy]methyl]benzene and
bis[(3-ethyloxetan-3-yl)methyl]ether. Of these compounds,
3-ethyl-3-(hydroxymethyl)oxetane and
bis[(3-ethyloxetan-3-yl)methyl]ether are especially preferred, from
the viewpoints of suitability for coating process and curability of
the resulting coated layer.
[0023] Such Components A for use in the present invention can be
prepared from an oxetane alcohol and a halide such as xylene
dichloride according to a known procedure. Such oxetane alcohol may
be prepared from, for example, trimethylolpropane and dimethyl
carbonate. An already available oxetane compound may be used as
Component A. For example, products under the trade names of "ARON
OXETANE OXT-101, 121, 211, 221, and 212" are commercially available
from Toagosei Co., Ltd.
[0024] Component B for use in the present invention can be any of
known epoxy compounds having at least one epoxy group per molecule
and can be, for example, aliphatic epoxy compounds, alicyclic epoxy
compounds, and aromatic epoxy compounds. Among them, compounds
having glycidyl group and compounds having epoxycyclohexane ring
are preferred, of which epoxy compounds having two or more epoxy
groups are preferred, from the viewpoint of high reaction rates.
Such aliphatic epoxy compounds include propylene glycol glycidyl
ether. Examples of alicyclic epoxy compounds include
3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexanecarboxylate and
bis-(3,4-epoxycyclohexyl)adipate. Examples of aromatic epoxy
compounds include bisphenol-A glycidyl ether and a condensate of
bisphenol-A with glycidyl ether, epichlorohydrin-modified novolak
resins, and epichlorohydrin-modified cresol resins.
[0025] Components B for use in the coating composition according to
the present invention can be those prepared according to common
procedures such as synthetic preparation from epichlorohydrin and
bisphenol-A. They are commercially available, for example, as
products from Daicel Chemical Industries, Ltd. under the trade
names of "Celloxide 2021", "Celloxide 2080", and "EPOLEAD GT400",
and a product from The Dow Chemical Company under the trade name of
"UVR6110".
[0026] The ratio (weight ratio) of Component A to Component B in
the resin composition according to the present invention is
preferably 2:8 to 8:2, namely, the ratio [(Component A)/(Component
B)] is preferably 0.25 to 4. When the composition is applied by
gravure printing or flexographic printing, the weight ratio is
preferably 4:6 to 8:2, more preferably 5:5 to 8:2, and most
preferably 6:4 to 8:2. Namely, the ratio [(Component A)/(Component
B)] is preferably 2/3 to 4, more preferably 1 to 4, and most
preferably 1.5 to 4. If the ratio (relative amount) of Component A
is larger than the above range, the resulting resin composition may
begin to cure slowly and may cure slowly, which results in lowered
productivity, or the composition may remain uncured in a regular
cure process. If the relative amount of Component B is larger than
the above range, the resin composition may have an excessively
large viscosity, and it may be difficult to apply the resin
composition uniformly by a coating procedure such as gravure
printing or flexographic printing; and termination of cure reaction
may often occur to yield a cured compound having a low molecular
weight, and the cured layer may become brittle.
[0027] The total amount of Component A and Component B for use in
the present invention is preferably 30 to 99 percent by weight
based on the total amount of the resin composition, typically for
yielding satisfactory coatability and curability. In particular,
when the resin composition according to the present invention is
used as a clear coating composition, the total amount is preferably
60 to 99 percent by weight, and more preferably 70 to 90 percent by
weight. When the resin composition according to the present
invention is used as a printing ink containing a pigment, the total
amount is preferably 30 to 90 percent by weight, and more
preferably 40 to 80 percent by weight.
[0028] When Component C is an epoxy-modified silicone, the content
of Component A is not specifically limited. When the composition is
applied, for example, according to a coating procedure such as
gravure printing or flexographic printing, the content of Component
A is preferably 10 to 75 percent by weight, and more preferably 20
to 70 percent by weight based on the total amount of the resin
composition (coating composition). In particular, when the resin
composition according to the present invention is used as a white
printing ink, i.e. when the coating layer contains large amounts of
additives such as pigments and lubricants, the content of Component
A is preferably 20 to 40 percent by weight. When the composition is
used as a clear coating ink, i.e. when the coating layer contains
small amounts of additives such as pigments and lubricants, the
content of Component A is preferably 50 to 70 percent by weight. If
the content of Component A exceeds 75 percent by weight, the resin
composition as the coating composition may begin to cure slowly, so
that the composition may cure insufficiently. Thus, the resulting
cured layer may be poor in thermal stability and solvent
resistance. In contrast, to cure sufficiently carried out in this
case, the production speed should be lowered to thereby lower the
productivity. If the content of Component A is less than 10 percent
by weight, termination of cure reaction may often occur, and the
cured composition may thereby have a low molecular weight or the
resulting cured layer (coating layer) may become brittle. In
addition, the resin composition may have an excessively high
viscosity, and it may be difficult to apply the composition
uniformly according to a coating procedure such as gravure printing
or flexographic printing.
[0029] As is mentioned above, when Component C is an epoxy-modified
silicone and when the composition is applied by coating through
gravure printing or flexographic printing, the content of Component
B is preferably 5 to 35 percent by weight based on the total amount
of the resin composition. Particularly, when the resin composition
according to the present invention is used as a white printing ink,
the content of Component B is preferably 5 to 25 percent by weight;
and when the composition is used as a clear coating ink, the
content is preferably 10 to 35 percent by weight. If the content of
Component B exceeds 35 percent by weight, termination of cure
reaction may often occur to give the cured composition having a low
molecular weight, and the cured layer may become brittle. In
addition, the resin composition may have an excessively high
viscosity, and it may be difficult to apply the composition
uniformly according to a coating procedure such as gravure printing
or flexographic printing. If the content of Component B is less
than 5 percent by weight, the resin composition may begin to cure
slowly, so that the composition may cure insufficiently. Thus, the
resulting cured layer may have lowered thermal stability and
solvent resistance. In contrast, to cure sufficiently in this case,
the production speed should be lowered to thereby lower the
productivity.
[0030] Component C for use in the present invention is at least one
silicone compound selected from the group consisting of
epoxy-modified silicones, fluorine-modified silicones,
amino-modified silicones, (meth)acrylic-modified silicones, and
polyether-modified silicones. These silicone compounds have one or
more epoxy groups, fluorine-containing substituents,
amino-containing substituents, (meth)acryloyl-containing
substituents, and polyether-chain-containing substituents
(hereinafter these are generically referred to as "introduced
substituent(s)"), respectively. Base silicones have only to be
polysiloxanes having siloxane bonds in their principal chain.
Examples of base silicones include dimethylsilicones with all side
chains and terminals being methyl groups, methylphenylsilicones
with part of side chains being phenyl groups, and
methylhydrogensilicones with part of side chains being hydrogen.
Among them, dimethylsilicones are preferred. The bonding
position(s) of introduced substituent(s) are not particularly
limited. For example, silicones may be represented by, for example,
following structural formulae. More specifically, they may have
introduced substituents at two terminals of principal chain
(two-terminal type as represented by following Structural Formula
(1)) or at one terminal (one-terminal type as represented by
following Structural Formula (2)), or in side chain (side-chain
type as represented by following Structural Formula (3)). The
silicones may also have introduced substituents both in side chain
and at one or both of terminals (two-terminals or one
terminal).
##STR00001##
[0031] In the formulae, X.sup.1 and X.sup.2 are the above-mentioned
introduced substituents; and each of R.sup.1, R.sup.2, and R.sup.3
is hydrogen atom or a hydrocarbon group which may contain oxygen
atom, nitrogen atom, and/or sulfur atom. These substituents are
preferably hydrogen atom, methyl group, or phenyl group, and more
preferably methyl group. Each of the repetition numbers "m" and "n"
is an integer of 1 or more.
[0032] When Component C is a fluorine-modified silicone, the
introduced substituent is not particularly limited but is
preferably a fluorinated alkyl group such as a group represented by
[--R.sup.4CF.sub.3], such as --CH.sub.2CH.sub.2CF.sub.3 and
--C.sub.3H.sub.6CF.sub.3. The substituent R.sup.4 is a hydrocarbon
group which may contain oxygen atom, nitrogen atom, and/or sulfur
atom.
[0033] The viscosity (at 23.+-.2.degree. C.) of a fluorine-modified
silicone for use as Component C in the present invention is
preferably 100000 mPas or less, and more preferably 50000 mPas or
less. If the viscosity exceeds 100000 mPas, the resin composition
may have an excessively high viscosity and may not be coated
satisfactorily.
[0034] When Component C is an amino-modified silicone, the
introduced substituent is an amino-containing substituent, is not
particularly limited, but is preferably an aminoalkyl group
represented typically by [--R.sup.5NH.sub.2],
[--R.sup.6NH--R.sup.7NH.sub.2], or [--R.sup.8NHC.sub.6H.sub.11],
such as --C.sub.3H.sub.6NH.sub.2 and
--C.sub.3H.sub.6NHC.sub.6H.sub.11. Each of the substituents
R.sup.5, R.sup.6, R.sup.7, and R.sup.8 is a hydrocarbon group which
may contain oxygen atom, nitrogen atom, and/or sulfur atom.
[0035] The viscosity (23.+-.2.degree. C.) of an amino-modified
silicone for use as Component C in the present invention is
preferably 100000 mPas or less, and more preferably 50000 mPas or
less. If the viscosity exceeds 100000 mPas, the resin composition
may have an excessively high viscosity and may not be coated
satisfactorily.
[0036] The functional group equivalent (unit: g/mol) of an
amino-modified silicone for use as Component C in the present
invention may be 500 or more (for example, 500 to 60000), and more
preferably 700 to 60000. If the functional group equivalent is less
than 500, a cure reaction may not proceed sufficiently due to cure
inhibition. If it is excessively high and exceeds 60000, the
advantages of addition of Component C (improvements in adhesion and
cure rate) may not be obtained effectively.
[0037] When Component C for use in the present invention is a
(meth)acrylic-modified silicone, the introduced substituent is a
substituent containing (meth)acryloyl group, is not particularly
limited, but is preferably [--R.sup.9OCOCH.dbd.CH.sub.2] or
[--R.sup.10OCOC(CH.sub.3).dbd.CH.sub.2], or the like. Specific
examples thereof include
--C.sub.3H.sub.6OCOC(CH.sub.3).dbd.CH.sub.2 and
--C.sub.3H.sub.6OCOCH.dbd.CH.sub.2. Each of the groups R.sup.9 and
R.sup.10 is a hydrocarbon group which may contain oxygen atom,
nitrogen atom, and/or sulfur atom.
[0038] The functional group equivalent (unit: g/mol) of a
(meth)acrylic-modified silicone for use as Component C in the
present invention may be 20000 or less (for example, 50 to 20000),
and is more preferably 100 to 15000. If the functional group
equivalent exceeds 20000, advantages of addition of Component C may
not be obtained effectively.
[0039] When Component C for use in the present invention is a
polyether-modified silicone, the introduced substituent is a
substituent containing two or more repeating units having an ether
bond, and is not particularly limited. Preferred examples thereof
include organic groups mainly containing an ethylene oxide unit or
propylene oxide unit, as represented by
[--R.sup.11(C.sub.2H.sub.4O).sub.aR.sup.12],
[--R.sup.13(C.sub.3H.sub.6O).sub.bR.sup.14], and [--R.sup.15
(C.sub.2H.sub.4O).sub.c(C.sub.3H.sub.6O).sub.dR.sup.16]. Each of
R.sup.11, R.sup.12, R.sup.13, R.sup.14, R.sup.15, and R.sup.16 is a
hydrocarbon group; each of the numbers "a" and "b" is an integer of
about 6 to about 30; and each of the numbers "c" and "d" is an
integer of about 1 to about 20.
[0040] The viscosity (23.+-.2.degree. C.) of a polyether-modified
silicone for use as Component C in the present invention is
preferably 100000 mPas or less, and more preferably 50000 mPas or
less. If the viscosity exceeds 100000 mPas, the resin composition
may have an excessively high viscosity and may not be coated
satisfactorily.
[0041] The HLB value (Hydrophile-Lipophile Balance) of a
polyether-modified silicone for use as Component C in the present
invention is not particularly limited, but is preferably 0 to 12,
and more preferably 0 to 10, for yielding satisfactory
compatibility. If the compound has a HLB value exceeding 12 and is
highly hydrophilic, it may become less compatible (miscible) with
other components.
[0042] When Component C for use in the present invention is an
epoxy-modified silicone, the introduced substituent is not
particularly limited and may be, for example, represented by
following structural formulae. The introduced substituent may be
one in which oxygen atom of epoxy group does not contain a cyclic
aliphatic structure (left formula; hereinafter referred to as
"aliphatic epoxy group") or one in which oxygen atom of epoxy group
contains a cyclic aliphatic structure (right formula; hereinafter
referred to as "alicyclic epoxy group").
##STR00002##
[0043] In these formulae, each of R.sup.17 and R.sup.18 is hydrogen
atom or a hydrocarbon group which may contain oxygen atom, nitrogen
atom, and/or sulfur atom. An epoxy-modified silicone compound
described in Japanese Unexamined Patent Application Publication
(JP-A) No. H10-259239, for example, can be used herein.
[0044] The functional group (epoxy group) equivalent (unit: g/mol)
of the silicone resin is preferably 300 to 5000, and more
preferably 400 to 4000, for yielding satisfactory curability.
[0045] Such epoxy-modified silicone can be obtained according to a
known process. For example, it can be obtained by a process in
which an alkenyl-containing epoxy compound is added to a
polyorganohydrogensiloxane typically using a catalyst; a process in
which an epoxy-containing hydrolyzable silane is subjected to
co-hydrolysis and polycondensation with another hydrolyzable
silane; or a process in which a hydroxyl-containing epoxy compound
is subjected to polycondensation with a silane or siloxane having
hydroxyl group or a hydrolyzable group.
[0046] Component C may further contain an organic group such as an
alkyl group and/or an aralkyl group, in addition to the introduced
substituents mentioned above.
[0047] Commercially available products can be used as Component C
in the present invention. Examples of products as fluorine-modified
silicones include products of Shin-Etsu Chemical Co., Ltd. under
the trade names of "FL-5, FL-100-100cs, FL-100-450cs, FL-100-1000
cs, FL-100-1000cs, X-22-821, and X-22-822", and products of Dow
Corning Toray Co., Ltd. under the trade name of "FS1265". Examples
of products as amino-modified silicones include products of
Shin-Etsu Chemical Co., Ltd. under the trade names of "KF-8005,
KF-859, KF-8008, X-22-3820W, KF-857, KF-8001, and KF-861". Examples
of products as (meth)acrylic-modified silicones include
methacrylic-modified silicone products of Shin-Etsu Chemical Co.,
Ltd. under the trade names of "X-22-2426, X-22-164A, X-22-164C,
X-22-2404, and X-24-8201", acrylic-modified silicone products of
Shin-Etsu Chemical Co., Ltd. under the trade names of "X-22-2445,
X-22-1602", and acrylic-modified silicone products of Degussa GmbH
under the trade names of "TEGO Rad 2400, 2500, 2600, and 2700".
Examples of products as polyether-modified silicones include
products of Shin-Etsu Chemical Co., Ltd. under the trade names of
"KF-351A, KF-352A, KF-353, KF-354L, KF-355A, KF-615A, KF-945,
KF-640, KF-642, KF-643, KF-6020, KF-6004, KF-6011, KF-6012,
KF-6015, KF-6017, X-22-6191, X-22-4515, and X-22-2516", and
products of Dow Corning Toray Co., Ltd. under the trade names of
"FZ-2110, FZ-2122, FZ-7006, FZ-2166, FZ-2164, FZ-2154, FZ-2191,
FZ-7001, FZ-2120, FZ-2130, FZ-720, FZ-7002, FZ-2123, FZ-2104,
FZ-77, FZ-2105, FZ-2118, FZ-7604, FZ-2161, FZ-2162, FZ-2203,
FZ-2207, FZ-2208, SH-8400, SH-8700, SH-3746, SH-3771, and SF-8491".
Examples of products as epoxy-modified silicones include products
of Shin-Etsu Chemical Co., Ltd. under the trade names of "KF-101,
KF-102, KF-105, KF-1001, X-22-163A, X-22-163B, X-22-163C,
X-22-169AS, X-22-169B, X-22-173DX, and X-22-2000".
[0048] In the present invention, the amount of Component C added is
preferably 0.1 to 40 parts by weight, more preferably 0.1 to 30
parts by weight, further more preferably 0.2 to 20 parts by weight,
still more preferably to 15 parts by weight, further more
preferably 1 to 10 parts by weight, and most preferably 2 to 10
parts by weight, to 100 parts by weight of the total amount of
Component A and Component B. If the amount of Component C is less
than part by weight, advantages of addition of Component C may be
insufficient, and cure may proceed at a lower rate and the
resulting resin layer may have lowered adhesion and toughness. If
the amount exceeds 40 parts by weight, advantages of addition of
Component A and Component B may not be exhibited effectively, or
the resin composition may have an excessively high viscosity and
may not be coated satisfactorily, thus causing, for example,
grazing (poor print quality) during printing.
[0049] Although being not particularly limited, when Component C is
an epoxy-modified silicone and the composition is applied by
coating through gravure printing or flexographic printing, the
content of Component C is preferably 0.1 to 20 percent by weight,
more preferably 0.2 to 10 percent by weight, and further more
preferably 0.3 to 5 percent by weight, based on the total amount of
the resin composition (the coating composition). If the content of
Component C is less than 0.1 percent by weight, advantages of
addition of Component C may be insufficient, and properties such as
solvent resistance, slipperiness, and water repellency may be
lowered. If the content exceeds 20 percent by weight, the resin
composition may have an excessively high viscosity, and it may be
difficult to apply the composition uniformly by gravure printing or
flexographic printing.
[0050] In the present invention, Component A is characterized by
giving a tough cured layer having a high molecular weight, because
this component is resistant to termination of cure reaction.
However, this component is also resistant to initiation of cure
reaction and thereby the curing process spends a long time to give
insufficient productivity. Alternatively, if the resin composition
for the resin layer is subjected to cure in a short time, it does
not sufficiently cure and gives a cured layer having insufficient
toughness. In contrast, on Component B, initiation of cure reaction
is rapidly carried out to thereby increase a production rate.
However, termination of cure often occurs, and the resulting cured
composition as a cured layer has a low molecular weight and thereby
has insufficient toughness. If the resin composition contains the
two components A and B, it may cure somewhat rapidly and have
productivity and toughness to some extent, but it is impossible to
yield a cured layer having sufficient toughness when the process is
conducted at a high speed. In contrast, when the resin composition
further contains a predetermined amount of Component C according to
the present invention, it cures dramatically rapidly as compared
with the composition containing Component A and Component B alone.
Accordingly, a resin layer can be cured rapidly upon a short time
application of active energy rays, the process can be carried out
at a higher speed, and the product can be obtained with improved
productivity. In addition, the cured layer can have a high
molecular weight and thereby have high toughness, because
termination of cure is inhibited. In other words, productivity and
toughness at high levels can be obtained simultaneously. It is
difficult to obtain these advantages when the resin composition is
a binary system containing Component C in combination with either
Component A or Component B. The composition should be a ternary
system.
[0051] The addition of Component C dramatically improves adhesion
of the resin composition to a plastic base film. It also improves
adhesion of the resin composition to another ink composition, and
thereby improves recoatability when another printing ink, for
example, is applied thereon.
[0052] When a regular resin composition contains silicone oil, cure
inhibition generally occurs, and the composition tends to cure
slowly and to adhere unsatisfactorily due to increased
releasability. In contrast to these tendencies, the system
according to the present invention containing the above-mentioned
specific modified silicone compound cures more rapidly and adheres
more satisfactorily. Although details remain unknown, the
improvements in cure rate and adhesion to a plastic film, and the
expression of recoatability with another ink are probably caused by
interactions between the three components, i.e., Components A, B,
and C. For example, the reactivity increases probably because
Component C surrounds Components A and B when the composition cures
upon application of active energy rays. When Component C is a
fluorine-modified silicone, the adhesion and recoatability are
improved probably because the fluorine-modified silicone as
Component C is involved in the reaction to alter wettability.
[0053] By compounding Components A, B, and C according to the
present invention, the composition can cure further rapidly to
attain higher productivity. The composition gives a cured layer
that has improved adhesion and toughness and can thereby
satisfactorily follow the deformation of a base shrink film during
shrinking process. After shrinking, the cured layer shows higher
scratch resistance and crumpling resistance. In addition, the cured
layer has effective properties such as resistance to chemicals,
slipperiness, water repellency, oil repellency, and less odor.
[0054] The resin composition according to the present invention
preferably contains a photoinitiator to exhibit curability with
active energy rays. Such photoinitiators for use in the present
invention are not particularly limited, of which photo-induced
cationic polymerization initiators are preferred. The photo-induced
cationic polymerization initiators include, but are not limited to,
diazonium salts, diaryliodonium salts, triarylsulfonium salts,
silanol/aluminum complexes, sulfonic acid esters, and
imidosulfonates, and the like. Among them, diaryliodonium salts and
triarylsulfonium salts are particularly preferred, from the
viewpoint of reactivity. The content of the photoinitiator is not
particularly limited, and is preferably 0.5 to 7 percent by weight,
and more preferably 1 to 5 percent by weight based on the total
amount of the resin composition.
[0055] When the resin composition according to the present
invention is used as a printing ink composition may further contain
additives such as pigments, dyestuffs, and others according to
necessity. The pigments can be organic or inorganic color pigments
and be selected and used according to the use. Examples such
pigments include white pigments including titanium dioxide
(titanium dioxide); cyan (blue) pigments such as copper
phthalocyanine blue; red pigments such as condensed azo pigments;
carbon blacks; aluminum flakes; and mica. In addition, extender
pigments can be used as pigments for the purpose such as adjusting
gloss or luster. Examples of such extender pigments include
alumina, calcium carbonate, barium sulfate, silica, and acrylic
beads. The content of such pigments can be freely set according
typically to the types of pigments and the target density of color,
but is preferably about 0.1 to about 70 percent by weight based on
the total amount (total weight) of the resin composition.
[0056] Among them, titanium dioxide is preferably used as a pigment
when the resin composition according to the present invention is
used as a white printing ink. The titanium dioxide can be any of
rutile (high-temperature tetragonal), anatase (low-temperature
tetragonal), and brookite (orthorhombic) titanium dioxides. It can
be obtained as commercially available products such as product as
titanium dioxide particles of Ishihara Sangyo Kaisha, Ltd. under
the trade name of "TIPAQUE", and products as titanium dioxide of
TAYCA CORPORATION under the trade name of "JR Series". The average
particle diameter of titanium dioxide particles is, for example,
about 0.01 to about 1 .mu.m, and preferably about 0.1 to about 0.5
.mu.m. When titanium dioxide particles form an aggregate, the
average particle diameter corresponds to the particle diameter of
the aggregate, i.e., secondary particle diameter. If the average
particle diameter is less than 0.01 .mu.m, the composition may not
be dispersed satisfactorily. If it exceeds 1 .mu.m, the label may
have a rough surface and may often have deteriorated appearance.
When the resin composition according to the present invention is
used as a white printing ink, the content of titanium dioxide is
preferably 20 to 60 percent by weight, and more preferably 30 to 55
percent by weight based on the total amount of the resin
composition. This range is set from the viewpoints of exhibiting
masking ability of titanium dioxide and inhibiting coarse
protrusion formations.
[0057] The resin composition according to the present invention
preferably contains a sensitizer according to necessity, for
yielding higher productive efficiency. This is particularly
effective when the above-mentioned titanium dioxide pigment, for
example, is used. The sensitizer in this case can be selected from
existing sensitizers in consideration typically of the type of
active energy rays to be used. Examples of sensitizers include (1)
amine sensitizers including aliphatic amines, aromatic amines, and
nitrogen-containing cyclic amines such as piperidine; (2) urea
sensitizers such as allyl urea and o-tolylthiourea; (3) sulfur
compound sensitizers such as sodium diethyldithiophosphate; (4)
anthracene sensitizers; (5) nitrile sensitizers such as
N,N-di-substituted p-aminobenzonitrile compounds; (6) phosphorus
compound sensitizers such as tri-n-butylphosphine; (7) nitrogen
compound sensitizers such as N-nitrosohydroxylamine derivatives and
oxazolidine compounds; and (8) chlorine compound sensitizers such
as carbon tetrachloride. Of these sensitizers, anthracene
sensitizers are preferred for their high sensitizing activities.
Among them, thioxanthone and 9,10-dibutoxyanthracene are more
preferred. The content of such sensitizers is not particularly
limited, but is preferably 0.1 to 5 percent by weight, and
particularly preferably 0.3 to 3 percent by weight based on the
total amount of the resin composition.
[0058] The resin composition according to the present invention may
contain lubricants according to necessity. Examples of lubricants
herein include waxes of every kind, including polyolefin waxes such
as polyethylene waxes; aliphatic amides; aliphatic esters; paraffin
wax; polytetrafluoroethylene (PTFE) wax; and carnauba wax.
[0059] When the resin composition according to the present
invention contains a solvent which is not involved in reactions and
is used mainly as a dispersing agent, the content of the solvent is
preferably 5 percent by weight or less, and more preferably 1
percent by weight or less. Most preferably, the composition does
not substantially contain a solvent. Examples of the solvent as
used herein include organic solvents such as toluene, xylenes,
methyl ethyl ketone, ethyl acetate, methyl alcohol, and ethyl
alcohol; and water. These solvents are generally used typically in
inks for gravure printing or flexographic printing to improve
coating processability, and compatibility and dispersibility of
respective components in the coating composition (printing inks).
Reactive diluents to be contained in the resin composition after
curing the resin composition are not included in the solvents as
defined herein. The resin composition according to the present
invention can exhibit excellent coatability and dispersibility
among components even when no solvent is contained. This minimizes
the amount of such a solvent and eliminates the need of removing
the solvent. Accordingly, a cured layer can be prepared at a higher
speed and lower cost, and loads on the environment can be
reduced.
[0060] The viscosity (23.+-.2.degree. C.) of the resin composition
according to the present invention is not particularly limited.
When the composition is to be applied by gravure printing, the
viscosity is preferably 10 to 2000 mPas, and more preferably 20 to
1000 mPas. If the viscosity exceeds 2000 mPas, the composition may
not be applied by gravure printing satisfactorily, thereby cause,
for example, "grazing", and this lowers decorating properties. If
the viscosity is less than 10 mPas, the composition may become
unstable during storage, and pigments and additives, for example,
may be likely to sink down. The viscosity of the resin composition
can be controlled by adjusting compounding ratios of Components A,
B, and C, and/or by using a thickening agent or a thinning agent.
The term "viscosity" as used herein means a value measured
according to the method specified in Japanese Industrial Standards
(JIS) Z 8803 with a Brookfield type viscometer (single-cylinder
rotary viscometer) at 23.+-.2.degree. C. and 60 rotate per minutes,
unless otherwise specified.
[0061] The resin composition according to the present invention is
preferably applied through gravure printing, flexographic printing,
or ink-jet printing from the viewpoints typically of cost,
productivity, and decorativeness of the printed resin layer. In
particular, the resin composition is preferably applied through
gravure printing.
[0062] The resin composition according to the present invention can
be used as printing inks for imparting decorativeness; as clear
coating composition (slippery vanishes) for improving slipperiness
of surface of labels; and as matt coating composition (mat
varnishes) for matt labels. Cured layers prepared from the resin
composition according to the present invention have excellent
scratch resistance and are suitably used typically as an outermost
layer (surface of top layer opposite to an adherend such as a
container) of labels such as a surface print or surface medium. In
addition, they have good recoatability and are also suitable as an
underlayer when two or more ink layers are laminated.
[0063] The resin composition according to the present invention may
be used for plastic labels. More specifically, they can be used
for, for example, orientation labels, shrink labels,
orientation/shrink labels, in-mold labels, tack labels, roll labels
(rolled stick-on labels), and heat-sensitive adhesive labels. Among
them, the resin composition according to the present invention is
particularly preferably used for shrink labels, because the
composition after curing adheres satisfactorily and shows excellent
following capability during shrinking process.
[0064] A plastic label having a cured layer (also referred to as
"coating layer") according to the present invention can be obtained
by applying the resin composition according to the present
invention to at least one side of a plastic film and curing the
composition with active energy rays. In the present invention, the
cured layer may be arranged in the label as a top surface layer,
such as an outermost layer or innermost layer, or as an underlayer
underlying another ink layer. When the cured layer is used as a top
surface layer, it effectively imparts properties such as scratch
resistance, surface thermal stability, solvent resistance, and
water repellency to the label. If the layer is used as an
underlayer, it effectively prevents delamination of another ink
which has been overcoated thereon. In particular, the cured layer
is preferably used for the formation of a shrink label, because the
cured layer shows good adhesion and satisfactory following
capability during shrinking process, and this effectively inhibit
whitening, delamination, and cracks (ink cracks) caused by
shrinkage.
[0065] The type of a plastic film for use in a plastic label
according to the present invention can be selected as appropriate
according typically to required properties, use, and cost, and is
not particularly limited. Examples of usable plastic films include
films of resins such as polyesters, polyolefins, polystyrenes,
poly(vinyl chloride)s, polyamides, aramid resins, polyimides,
polyphenylenesulfides, and acrylic resins. Among them, preferred
are polyester films, polyolefin films, polystyrene films, and
poly(vinyl chloride) films, of which polyester films and polyolefin
films are more preferred. The material polyester can be, for
example, a poly(ethylene terephthalate) (PET) or
poly(ethylene-2,6-naphthalenedicarboxylate) (PEN). The material
polyolefin can be, for example, polypropylene, polyethylene, or a
cyclic olefin.
[0066] The plastic film may be a single-layer film or a multilayer
film including two or more film layers arranged according typically
to required properties and use. When the plastic film is a
multilayer film, it may be a multilayer film including film layers
composed of different resins. The multilayer film can be, for
example, three-layered film including a central layer and two
surface layers (inner layer and outer layer), in which the central
layer is composed of a polyolefin resin or a polystyrene resin, and
the surface layers are composed of a polyester resin. The plastic
film can be any of an unoriented film, a uniaxially oriented film,
and a biaxially oriented film, selected according typically to
required properties and use. In particular, when the plastic label
is a shrink label, the plastic film is often a uniaxially or
biaxially oriented film, of which generally used is a film which
has strong orientation in a film width direction (direction to be a
circumferential direction of the label), namely, a film which has
been substantially uniaxially oriented in a widthwise
direction.
[0067] The plastic film can be prepared according to a common
procedure such as film formation using melting state or film
formation using solution. A commercially available plastic film can
also be used herein. The plastic film may have a surface which has
been subjected to a common surface treatment such as corona
discharge treatment or treatment with a primer, if necessary.
[0068] A polyester film such as a PET film may be prepared by film
formation using melting state, for example, in the following
manner. A material for the film is polymerized according to a known
procedure. A polyester, for example, may be prepared by a process
in which terephthalic acid and ethylene glycol as starting
materials are subjected to direct esterification to yield a low
molecular weight poly(ethylene terephthalate), and this is further
subjected to polycondensation by the catalysis typically with
antimony trioxide to yield a polymer. Where necessary, another
monomer such as 1,4-cyclohexanedimethanol may be copolymerized. The
material thus obtained is extruded from a T-die through a
single-screw or double-screw extruder to thereby yield an
unoriented film. In this case, an unoriented multilayer film having
layers of different kinds of resins can be obtained, for example,
through coextrusion. The unoriented film is generally subjected to
orientation to yield a plastic film, while the processes vary with
the use. The orientation may be biaxial orientation in a
longitudinal direction (machine direction (MD)) and a widthwise
direction (transverse direction (TD)) or monoaxial orientation in a
longitudinal or widthwise direction. The orientation procedure can
be any of orientation using a roll, orientation using a tenter, and
orientation using a tube. While depending on the type of a polymer
to be used, the orientation procedure of a plastic film, for
example, if used for the preparation of a shrink label, is often
conducted by orientation the film at a temperature between the
glass transition temperature (Tg) of the polymer and a temperature
about 50.degree. C. higher than the glass transition temperature
(Tg+50.degree. C.) in a longitudinal direction, for example, at a
orientation ratio of about 1.01 to about 3 times, and preferably
about 1.05 to about 1.5 times and then orientation in a widthwise
direction at a orientation ratio of about 3 to about 10 times, and
preferably about 4 to about 6 times, if the need arises.
[0069] The rate of thermal shrinkage (90.degree. C., 10 seconds) of
the plastic film is not particularly limited. When the plastic film
is used for the preparation of a shrink label, the plastic film
preferably has a thermal shrinkage of -3% to 15% in a longitudinal
direction and of 20% to 80% in a widthwise direction.
[0070] The thickness of the plastic film may vary depending on its
use, is not particularly limited, but is preferably 10 to 200
.mu.m. When the plastic film is used for the preparation of a
shrink label, for example, the thickness is preferably 20 to 80
.mu.m, and more preferably 30 to 60 .mu.m.
[0071] The thickness of a resin layer formed by the application of
the resin composition according to the present invention may vary
depending on its use, is not particularly limited, but is
preferably 0.1 to 15 .mu.m, and especially preferably 0.5 to 10
.mu.m. It may be difficult to form a uniform resin layer when the
resin layer has a thickness of less than 0.1 .mu.m. If the
resulting uneven resin layer is used, for example, as a print
layer, it may have deteriorated decorativeness or may not be
printed in accordance with the design due typically to partial
"grazing". In contrast, when the resin layer has a thickness
exceeding 15 .mu.m, a large amount of the resin composition may be
required, and this may invite increased cost, or it may be
difficult to apply the composition to form a uniform resin layer.
Alternatively or in addition, the resulting cured layer may be
brittle and be likely to delaminate. In particular, when the cured
layer is a white ink layers the thickness of the resin layer is
preferably 3 to 10 .mu.m for achieving sufficient masking. When the
cured layer is a clear coating layer, the thickness is preferably
0.2 to 3 .mu.m, for yielding satisfactory transparency. It should
be noted that the cured layer formed according to the present
invention varies little in its thickness before and after cure.
[0072] Cured layers obtained according to the present invention can
be used as various layers, such as print ink layers, topcoat
layers, and anchor coat layers. Particularly, they can exhibit
excellent advantages when used as surface print ink layers and
topcoat layers requiring scratch resistance, and as anchor coat
layers underlying another ink layer.
[0073] The angle of contact between water and a surface of a cured
layer of a plastic label according to the present invention is not
particularly limited, but is preferably 90 degrees or more, and
more preferably 100 degrees or more. If the angle of contact
between water and the cured layer is less than 90 degrees, the
surface of the cured layer may be likely to be soiled.
[0074] A plastic label according to the present invention may
further have another print layer in addition to a cured layer
formed according to the present invention. In this case, such
another print layer can be formed according to a common printing
procedure such as gravure printing or flexographic printing. A
printing ink for use in the formation of the print layer contains,
for example, a pigment, a binder resin, and a solvent. Examples of
the binder resin include common or regular resins such as acrylic
resins, urethane resins, polyamides, vinyl chloride-vinyl acetate
copolymers, celluloses, and nitrocelluloses. The thickness of the
print layer is not particularly limited and is, for example, about
0.1 to about 10 .mu.m.
[0075] A plastic label according to the present invention may
further contain one or more other layers in addition to the cured
layer formed according to the present invention. Examples of such
other layers include anchor coat layers, primer coat layers, layers
of nonwoven fabrics, and layers of paper.
[0076] Plastic labels according to the present invention are
generally used as labeled containers after being affixed to
containers. Examples of such containers include soft drink bottles
such as PET bottles; home-delivered milk containers; containers for
foodstuffs such as seasonings; alcoholic drink bottles; containers
for pharmaceutical preparations; containers for chemicals such as
detergents and aerosols (sprays); and pot noodle containers.
Materials for these containers include plastics such as PET; glass;
and metals. Plastic labels according to the present invention may
also be used to be applied to other adherends than containers.
[0077] Some embodiments of how the resin composition and plastic
labels according to the present invention are prepared, and how the
plastic labels are attached to containers will be illustrated
below. In the following embodiments, a shrink film that shrinks in
a widthwise direction is used as a plastic film to prepare a
cylindrical shrink label. It should be noted, however, this is
illustrated only by way of example, and the ways how the
composition and plastic labels are prepared and how the plastic
labels are attached to containers are not limited thereto.
[0078] In the following illustrations, the term "plastic film"
refers to an original film before bearing a cured layer; the term
"(long) plastic label" refers to the plastic film bearing a cured
layer formed according to the present invention. In the attachment
of the label to a container, the term "long cylindrical plastic
label" refers to the long plastic label which has been processed to
be cylindrical while leaving it long.
[Preparation of Resin Composition]
[0079] Above-mentioned Component A, Component B, Component C, and a
photoinitiator are mixed to yield the resin composition. Additives
such as pigments and sensitizers, if used, are also mixed
simultaneously with the above components. The mixing is conducted
typically using a mixer, a mill, and/or a kneader. Examples of the
mixer include butterfly mixers, planetary mixers, pony mixers,
dissolvers, tank mixers, homomixers, and homodispers. Examples of
mills include roll mills, sand mills, ball mills, bead mills, and
line mills. The mixing duration (residual duration) in the mixing
is preferably 10 to 120 minutes. Where necessary, the resulting
resin composition may be filtrated before use.
[Preparation of Plastic Label]
[0080] A resin layer (before cure) is formed by coating the resin
composition according to the present invention to a plastic film
typically through gravure, flexographic, or ink-jet printing. The
coating may be conducted by in-line coating in which the
composition is applied during the preparation of the plastic film,
for example, before orientation (as an unorientated film) or after
monoaxial orientation in a machine direction; or by off-line
coating in which the composition is applied after the preparation
of the plastic film. The coating procedure is not particularly
limited, but off-line coating is preferred from the viewpoints of
productivity and processability including cure processability.
[0081] Next, curing of the resin layer is conducted. The curing is
preferably conducted in a series of steps including the coating
step, from the viewpoint of productivity. The curing is conducted
by the irradiation with an active energy ray using an ultraviolet
(UV) lamp, an ultraviolet LED, or ultraviolet laser, or the like.
The active energy ray to be applied may vary depending on the
composition of the resin composition, is not particularly limited,
but is preferably ultraviolet rays (near-ultraviolet rays) having
wavelengths of 200 to 460 nm (more preferably 300 to 460 nm), from
the viewpoint of curability. The irradiation is preferably
conducted at an irradiation intensity of 150 to 1000 mJ/cm.sup.2
for a irradiation time of to 3 seconds.
[0082] The long plastic label thus obtained is slit to
predetermined widths, and wound to yield rolls.
[Processing of Long Plastic Label]
[0083] Next, one of the rolls is unwound and formed into a round
cylinder so that a widthwise direction of the long plastic film
stands a circumferential direction of the cylinder. Specifically,
the long plastic label is formed into a cylinder, and a solvent,
such as tetrahydrofuran (THF), and an adhesive (these components
are hereinafter referred to as "solvent and other components") are
applied in a swath about 2 to 4 mm wide in a longitudinal direction
to an inner surface of one lateral end of the label. The label is
then cylindrically wound so that the portion where the solvent and
other components are applied is overlaid the outer surface of the
other lateral end of the label at a position of 5 to 10 mm inside
from the other lateral end, affixed and adhered (center-sealed).
Thus, a long cylindrical plastic label is obtained as a continuous
long cylindrical plastic label. It is desirable that no cured layer
is arranged in the portion where the solvent and other components
are applied and are subjected to adhesion.
[0084] When perforations for tearing the label are arranged,
perforations with predetermined lengths and intervals (pitches) are
formed in a longitudinal direction. The perforations can be
arranged according to a common procedure. They can be arranged, for
example, by pressing a disk-like blade peripherally having cutting
edges and non-cutting portions alternately, or by using laser. The
step of arranging perforations can be carried out as appropriate in
a suitable stage, such as after the printing step, or before or
after the step of processing to form a cylindrical label.
[Labeled Container]
[0085] Finally, the above-prepared long cylindrical plastic label
is cut, attached to a predetermined container, shrunk by heat
treatment, thereby brought into intimate contact with the
container, and yields a labeled container. More specifically, the
long cylindrical plastic label is fed to an automatic labeling
machine (shrink labeler), cut to a required length, fit onto a
container filled with a content, subjected to thermal shrinkage by
allowing the article to pass through a hot-air tunnel or steam
tunnel at a predetermined temperature or by heating the article
with radial heat such as infrared rays, thereby brought into
intimate contact with the container, and thus yields a labeled
container. The heat treatment may be carried out, for example, by
treating the article with steam at 80.degree. C. to 100.degree. C.
For example, the article may be allowed to pass through a heating
tunnel filled with steam.
EXAMPLES
[0086] The present invention will be illustrated in further detail
with reference to several examples below. It should be noted,
however, these examples are never construed to limit the scope of
the present invention. Methods for measuring properties and methods
for evaluating advantageous effects in the present invention
including the following examples are as follows.
[Methods for Measuring Properties and Evaluating Advantages]
(1) Gravure Printability
[0087] Gravure printing was carried out under printing conditions
in examples and comparative examples, and how are the resulting
prints were visually observed. A sample having a print in exact
accordance with the printing cylinder was evaluated as having good
gravure printability (.smallcircle.), and a sample having a print
not in accordance with the printing cylinder was evaluated as
having poor gravure printability (x).
(2) Curability (Initial Tack)
[0088] Curing was conducted at a process speed in ultraviolet
irradiation of 50, 70, or 100 m/minute in the examples and
comparative examples. The surfaces of cured layers were touched by
a finger immediately after curing, and whether or not the ink was
attached to the finger was visually observed. The curability was
evaluated according to the following criteria:
.circleincircle.: The ink was not attached at a process speed of
100 m/minute; .smallcircle.: The ink was not attached at a process
speed of 70 m/minute, but was attached at a process speed of 100
m/minute; .DELTA.: The ink was not attached at a process speed of
50 m/minute, but was attached at a process speed of 70 m/minute; x:
The ink was attached even at a process speed of 50 m/minute.
(3) Adhesion (Tape Peeling Test)
[0089] Tests were conducted according to JIS K 5600, except for not
forming cross cuts. NICHIBAN tapes (18 mm wide) were affixed to
surfaces of resin layers of plastic labels prepared according to
the examples and comparative examples, were peeled off at an angle
of 90 degrees, the areas of residual resin layers were observed in
regions each 5 mm wide and 5 mm long, and the adhesion was
evaluated according to the following criteria:
90% or more: Good adhesion (.smallcircle.); 80% or more and less
than 90%: Somewhat poor but usable adhesion (.DELTA.); Less than
80%: Poor adhesion (x)
(4) Crumpling Resistance
[0090] Sample pieces 100 mm long and 100 mm wide were sampled from
plastic labels prepared according to the examples and comparative
examples. The sample pieces were held by both hands at both ends,
and crumpled ten times by both hands. The areas of residual cured
layers on the surfaces of the crumpled sample pieces were visually
observed, and the crumpling resistance was evaluated as follows. A
sample showing a residual area of 90% or more was evaluated as
having good crumpling resistance (.smallcircle.), and one showing a
residual area of less than 90% was evaluated as having poor
crumpling resistance (x).
(5) Scratch Resistance
[0091] Sample pieces 100 mm long and 100 mm wide were sampled from
plastic labels prepared according to the examples and comparative
examples. The sample pieces were placed on a flat table, the
surfaces of the sample pieces on the side bearing a cured layer
were rubbed with the back of a finger nail ten times in
back-and-forth motion in a region of 20 mm in a longitudinal
direction, the surfaces were then observed, and the scratch
resistance was evaluated according to the following criteria:
The cured layer was not at all delaminated: Good scratch resistance
(.smallcircle.); The cured layer was partially delaminated:
Somewhat poor but usable scratch resistance (.DELTA.); The cured
layer was remarkably delaminated: Poor scratch resistance (x)
(6) Overprintability (Recoatability on Overprinting)
[0092] The each resin composition prepared according to the
examples and comparative examples was overcoated by printing onto
cured layers of plastic labels prepared by using the corresponding
composition prepared according to the examples and comparative
examples. The conditions for printing and curing were similar to
the conditions for printing and curing the resin composition in the
examples and comparative examples.
[0093] The adhesion of the overcoated ink layers was evaluated by
the same procedure according to the same criteria as in "(3)
Adhesion".
(7) Thicknesses of Film Layer and Cured Layer
[0094] The thicknesses of films were measured with a stylus-type
thickness gauge. The thicknesses of cured layers were measured as
the step height between a portion where a cured layer was arranged
(coated surface) and a portion where no cured layer was arranged
(non-coated surface) with a three-dimensional microscope (Keyence
Corporation; VK8510).
(8) Thermal Shrinkage (90.degree. C.) of Plastic Film
[0095] Rectangular sample pieces were cut out from the plastic
films in a measurement direction (longitudinal direction or
widthwise direction). The sample pieces had a length of 200 mm
(gauge length: 150 mm) and a width of 10 mm.
[0096] The sample pieces were subjected to heat treatment (under no
load) in hot water at 90.degree. C. for 10 seconds, the differences
in gauge length between before and after the heat treatment and
thermal shrinkages were calculated according to the following
calculation formula:
Thermal shrinkage (%)=(L.sub.0-L.sub.1)/L.sub.0.times.100
[0097] L.sub.0: Gauge length before the heat treatment
[0098] L.sub.1: Gauge length after the heat treatment
(9) Viscosity
[0099] The viscosities were measured according to JIS Z 8803 with a
Brookfield type viscometer (single-cylinder rotary viscometer)
supplied from Toki Sangyo Co., Ltd. at 23.+-.2.degree. C. and 60
rotate per minutes.
[0100] Examples are shown below.
Example 1
[0101] The active energy ray-curable resin composition (white ink)
was prepared by blending, in amounts shown in Table 1,
bis[(3-ethyloxetan-3-yl)methyl]ether (product of Toagosei Co., Ltd.
under the trade name of "ARON OXETANE OXT-221") as Component A
(A1); an epoxy monomer (product of The Dow Chemical Company under
the trade name of "UVR-6110") as Component B (B1); a
fluorine-modified silicone (product of Shin-Etsu Chemical Co., Ltd.
under the trade name of "X-22-821") as Component C (C1); a
photoinitiator (product of The Dow Chemical Company under the trade
name of "UVI-6992"); titanium dioxide (product of TAYCA CORPORATION
under the trade name of "JR-809") as a white pigment; and
dibutoxyanthracene (product of Kawasaki Kasei Chemicals Ltd.) as a
sensitizer. No solvent was used herein.
[0102] The prepared resin composition was applied to all over one
side of a polyester shrink film (product of Toyobo Co., Ltd. under
the trade name of "Spaceclean S7042", film thickness: 45 .mu.m to
form a resin layer 3.6 .mu.m thick by gravure printing at a process
speed of 50 m/minute using a bench gravure printing machine
(product of Nissio Gravure Co., Ltd. under the trade name of "GRAVO
PROOF MINI") and a gravure cylinder with 90 lines/cm having a cell
depth of 30 .mu.m, and the gravure printability was evaluated.
[0103] Subsequently, the shrink film coated with the resin
composition was irradiated with rays at 240 W/cm using an
ultraviolet irradiator (product of FUSION UV SYSTEMS JAPAN K.K.
under the trade name of "LIGHT HAMMER 10"; output: 75%, D bulb),
and the curability was evaluated. The irradiation intensities of
the irradiator were measured with the "UV Power Puck" (trade name;
product of EIT Inc.) and were 50 mJ/cm.sup.2 (UVC), 310 mJ/cm.sup.2
(UVB), 550 mJ/cm.sup.2 (UVA), and 370 mJ/cm.sup.2 (UVV) at a
conveyor speed (process speed) of 10 m/minute.
[0104] The adhesion, crumpling resistance, scratch resistance, and
overprintability of the plastic label prepared at a conveyor speed
of 50 m/minute and having a cured layer thickness of 3.6 .mu.m were
evaluated.
[0105] As is demonstrated in Table 1, the prepared resin
composition excelled in gravure printability and curability, and
the plastic label was good in adhesion, crumpling resistance,
scratch resistance, and overprintability.
Examples 2 to 8
[0106] A series of the resin composition and plastic labels were
prepared by the procedure of Example 1, except for changing
conditions such as the amounts of respective components, and the
types of Component C and the pigment as shown in Table 1.
[0107] The each prepared resin composition excelled in gravure
printability and curability, and the plastic labels were good in
adhesion, crumpling resistance, scratch resistance, and
overprintability.
Comparative Example 1
[0108] The resin composition and a plastic label were prepared by
the procedure of Example 2, except for not using Component A as
shown in Table 1.
[0109] The resin composition had a high viscosity and was poor in
gravure printability and curability, and the plastic label was poor
in adhesion, crumpling resistance, scratch resistance, and
overprintability.
Comparative Example 2
[0110] The resin composition and a plastic label were prepared by
the procedure of Example 2, except for not using Component B as
shown in Table 1.
[0111] The resin composition cured slowly and was poor in
productivity, and the plastic label was poor in adhesion, crumpling
resistance, scratch resistance, and overprintability.
Comparative Example 3
[0112] The resin composition and a plastic label were prepared by
the procedure of Example 2, except for not using Component C as
shown in Table 1.
[0113] The resin composition cured slowly and was poor in
productivity, and the plastic label was poor in adhesion, crumpling
resistance, scratch resistance, and overprintability.
Examples 9 to 16
[0114] A series of the resin composition and plastic labels were
prepared by the procedure of Examples 1 to 8, except for using an
amino-modified silicone as Component C and for changing conditions
such as the amounts of respective components and the type of
pigment as shown in Table 2.
[0115] The each resin composition excelled in gravure printability
and curability, and the plastic labels were good in adhesion,
crumpling resistance, scratch resistance, and overprintability.
Comparative Examples 4 and 5
[0116] A series of the resin composition and plastic labels were
prepared by the procedure of Example 10, except for not using
Component A and Component B, respectively, as shown in Table 2.
[0117] The each resin composition cured slowly and was poor in
productivity, and the plastic labels were poor in adhesion,
crumpling resistance, scratch resistance, and overprintability. The
resin composition prepared according to Comparative Example 4 was
also poor in gravure printability.
Examples 17 to 25
[0118] A series of the resin composition and plastic labels were
prepared by the procedure of Examples 1 to 8, except for using a
methacrylic-modified silicone or an acrylic-modified silicone,
respectively, as Component C and for changing conditions such as
the amounts of respective components and the type of pigment as
shown in Table 3.
[0119] The each resin composition excelled in gravure printability
and curability, and the plastic labels were good in adhesion,
crumpling resistance, scratch resistance, and overprintability.
Comparative Examples 6 and 7
[0120] A series of the resin composition and plastic labels were
prepared by the procedure of Example 18, except for not using
Component A and Component B, respectively, as shown in Table 3.
[0121] The each resin composition cured slowly and was poor in
productivity, and the plastic labels were poor in adhesion,
crumpling resistance, scratch resistance, and overprintability. The
resin composition prepared according to Comparative Example 6 was
also poor in gravure printability.
Examples 26 to 32
[0122] A series of the resin composition and plastic labels were
prepared by the procedure of Examples 1 to 8, except for using a
polyether-modified silicone as Component C and for changing
conditions such as the amounts of respective components and the
type of pigment, as shown in Table 4.
[0123] The each resin composition excelled in gravure printability
and curability, and the plastic labels were good in adhesion,
crumpling resistance, scratch resistance, and overprintability.
Comparative Examples 8 and 9
[0124] A series of the resin composition and plastic labels were
prepared by the procedure of Example 27, except for not using
Component A and Component B, respectively, as shown in Table 4.
[0125] The each resin composition cured slowly and was poor in
productivity, and the plastic labels were poor in adhesion,
crumpling resistance, scratch resistance, and overprintability. The
resin composition prepared according to Comparative Example 8 was
also poor in gravure printability.
[0126] In addition, labeled containers were prepared using the
plastic labels of Examples 1 to 32. Specifically, the plastic
labels prepared at a conveyor speed of 50 m/minute were formed into
round cylinders so that the printed surface constituted an inner
side, the lengths in circumferential direction of the cylinders
were adjusted so that they would be attached to bodies of PET
bottles with thermal shrinkage of 20%, both ends of them were fused
and adhered with each other, and thereby yielded cylindrical
plastic labels. The cylindrical plastic labels were attached to
500-ml PET bottles, subjected to shrinking in a steam tunnel at an
atmospheric temperature of 90.degree. C., and thereby yielded the
labeled containers. The labeled containers had excellent finished
quality.
[0127] [Table 1]
TABLE-US-00001 TABLE 1 Exam- Exam- Exam- Exam- Exam- Exam- Exam-
Exam- Comp. Comp. Comp. ple 1 ple 2 ple 3 ple 4 ple 5 ple 6 ple 7
ple 8 Ex. 1 Ex. 2 Ex. 3 Amount Component A1 37 37 37 37 37 37 53 53
0 51 37 A (oxetane compound) Component B1 16 16 16 16 16 16 24 24
51 0 16 B (epoxy compound) Component C1 1 5 0.1 20 5 5 5 5 0 C
(fluorine- C2 5 modified silicone) C3 5 Photoinitiator 3 3 3 3 3 3
3 3 3 3 3 Sensitizer 1 1 1 1 1 1 1 1 1 1 1 Pigment (white) 40 40 40
40 40 40 40 40 40 Pigment (red) 16 Pigment (blue) 16 Property
Gravure printability .largecircle. .largecircle. .largecircle.
.largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. X .largecircle. .largecircle. Curability (initial
tack) .circleincircle. .circleincircle. .largecircle. .largecircle.
.circleincircle. .circleincircle. .circleincircle. .largecircle. X
X X Adhesion (tape peeling) .largecircle. .largecircle.
.largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. .largecircle. X X X Crumpling resistance
.largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. .largecircle. .largecircle. .largecircle. X X X
Scratch resistance .largecircle. .largecircle. .largecircle.
.largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. X X X Overprintability .largecircle. .largecircle.
.largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. .largecircle. X X X
[0128] [Table 2]
TABLE-US-00002 TABLE 2 Exam- Exam- Exam- Exam- Exam- Exam- Exam-
Exam- Comp. Comp. ple 9 ple 10 ple 11 ple 12 ple 13 ple 14 ple 15
ple 16 Ex. 4 Ex. 5 Amount Component A A1 37 37 37 37 37 37 52 52 0
51 (oxetane compound) Component B1 16 16 16 16 16 16 23 23 51 0 B
(epoxy compound) Component C4 1 5 0.1 20 5 5 5 5 C (amino- C5 5
modified C6 silicone) 5 5 5 Photoinitiator 3 3 3 3 3 3 3 3 3 3
Sensitizer 1 1 1 1 1 1 1 1 1 1 Pigment (white) 40 40 40 40 40 40 40
40 Pigment (red) 16 Pigment (blue) 16 Property Gravure printability
.largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. .largecircle. .largecircle. .largecircle. X
.largecircle. Curability (initial tack) .circleincircle.
.circleincircle. .largecircle. .largecircle. .circleincircle.
.circleincircle. .circleincircle. .largecircle. X X Adhesion (tape
peeling) .largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. .largecircle. .largecircle. .largecircle. X X
Crumpling resistance .largecircle. .largecircle. .largecircle.
.largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. X X Scratch resistance .largecircle. .largecircle.
.largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. .largecircle. X X Overprintability .largecircle.
.largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. .largecircle. .largecircle. X X
[0129] [Table 3]
TABLE-US-00003 TABLE 3 Exam- Exam- Exam- Exam- Exam- Exam- Exam-
Exam- Exam- Comp. Comp. ple 17 ple 18 ple 19 ple 20 ple 21 ple 22
ple 23 ple 24 ple 25 Ex. 6 Ex. 7 Amount Component A1 37 37 37 37 37
37 37 53 53 0 51 A (oxetane compound) Component B1 16 16 16 16 16
16 16 24 24 51 0 B (epoxy compound) Component (methacrylic- C7 0.5
3 0.1 20 3 3 3 3 C modified C8 3 silicone) (acrylic C9 3 modified
C10 silicone) 3 Photoinitiator 3 3 3 3 3 3 3 3 3 3 3 Sensitizer 1 1
1 1 1 1 1 1 1 1 1 Pigment (white) 40 40 40 40 40 40 40 40 40
Pigment (red) 16 Pigment (blue) 16 Pro- Gravure printability
.largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. X .largecircle. perty Curability (initial tack)
.circleincircle. .circleincircle. .largecircle. .largecircle.
.circleincircle. .circleincircle. .circleincircle. .circleincircle.
.largecircle. X X Adhesion (tape peeling) .largecircle.
.largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. .largecircle. .largecircle. .largecircle. X X
Crumpling resistance .largecircle. .largecircle. .largecircle.
.largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. .largecircle. X X Scratch resistance .largecircle.
.largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. .largecircle. .largecircle. .largecircle. X X
Overprintability .largecircle. .largecircle. .largecircle.
.largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. .largecircle. X X
[0130] [Table 4]
TABLE-US-00004 TABLE 4 Exam- Exam- Exam- Exam- Exam- Exam- Exam-
Comp. Comp. ple 26 ple 27 ple 28 ple 29 ple 30 ple 31 ple 32 Ex. 8
Ex. 9 Amount Component A1 37 37 37 37 37 53 53 0 51 A (oxetane
compound) Component B1 16 16 16 16 16 24 24 51 0 B (epoxy compound)
Component C11 1 5 0.1 5 5 5 5 C (polyether- C12 5 modified C13
silicone) 5 Photoinitiator 3 3 3 3 3 3 3 3 3 Sensitizer 1 1 1 1 1 1
1 1 1 Pigment (white) 40 40 40 40 40 40 40 Pigment (red) 16 Pigment
(blue) 16 Property Gravure printability .largecircle. .largecircle.
.largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. X .largecircle. Curability (initial tack)
.circleincircle. .circleincircle. .largecircle. .circleincircle.
.circleincircle. .circleincircle. .largecircle. X X Adhesion (tape
peeling) .largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. .largecircle. .largecircle. X X Crumpling resistance
.largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. .largecircle. .largecircle. X X Scratch resistance
.largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. .largecircle. .largecircle. X X Overprintability
.largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. .largecircle. .largecircle. X X
[0131] Components A, B, and C and other additives in Tables 1 to 4
are as follows. The amounts in these tables are indicated in unit
of "part by weight".
[0132] Component A
[0133] A1: product of Toagosei Co., Ltd. under the trade name of
"ARON OXETANE OXT-221"
[0134] Component B
[0135] B1: product of The Dow Chemical Company under the trade name
of "UVR-6110"
[0136] Component C
[0137] C1: product of Shin-Etsu Chemical Co., Ltd. under the trade
name of "X-22-821" (fluorine-modified)
[0138] C2: product of Shin-Etsu Chemical Co., Ltd. under the trade
name of "FL-100-450cs" (fluorine-modified)
[0139] C3: product of Shin-Etsu Chemical Co., Ltd. under the trade
name of "FL-100-1000cs" (fluorine-modified)
[0140] C4: product of Shin-Etsu Chemical Co., Ltd. under the trade
name of "KF-8005" (amino-modified)
[0141] C5: product of Shin-Etsu Chemical Co., Ltd. under the trade
name of "KF-859" (amino-modified)
[0142] C6: product of Shin-Etsu Chemical Co., Ltd. under the trade
name of "KF-8008" (amino-modified)
[0143] C7: product of Shin-Etsu Chemical Co., Ltd. under the trade
name of "X-24-8201" (methacrylic-modified)
[0144] C8: product of Shin-Etsu Chemical Co., Ltd. under the trade
name of "X-22-164C" (methacrylic-modified)
[0145] C9: product of Shin-Etsu Chemical Co., Ltd. under the trade
name of "X-22-2445" (acrylic-modified)
[0146] C10: product of Shin-Etsu Chemical Co., Ltd. under the trade
name of "X-22-1602" (acrylic-modified)
[0147] C11: product of Shin-Etsu Chemical Co., Ltd. under the trade
name of "X-22-6191" (polyether-modified)
[0148] C12: product of Shin-Etsu Chemical Co., Ltd. under the trade
name of "KF-6015" (polyether-modified)
[0149] C13: product of Shin-Etsu Chemical Co., Ltd. under the trade
name of "X-22-2516" (polyether-modified)
[0150] Photoinitiator: The Dow Chemical Company under the trade
name of "UVI-6992"
[0151] Sensitizer: product of Kawasaki Kasei Chemicals Ltd.,
dibutoxyanthracene
[0152] Pigment (white): product of TAYCA CORPORATION under the
trade name of "JR-809" (titanium dioxide)
[0153] Pigment (red): product of Ciba Specialty Chemicals
Corporation under the trade name of "CROMOPHTAL RED 2030 (SA)"
(diketopyrrolopyrrole)
[0154] Pigment (blue): product of Ciba Specialty Chemicals
Corporation under the trade name of "IRGALITE BLUE BLPO" (copper
phthalocyanine blue)
[0155] In addition, examples in which an epoxy-modified silicone
was used as Component C, and Components A, B and/or additives were
changed will be illustrated. In following Examples 33 to 40 and
Comparative Examples 10 to 13, the gravure printability,
curability, resistance to chemicals, water repellency, and
suitability for shrinking were evaluated according to the following
methods. The other properties were evaluated according to the
above-mentioned methods.
Methods for Evaluating Advantageous Effects
Examples 33 to 40 and Comparative Examples 10 to 13
(10) Gravure Printability
[0156] Gravure printing was carried out by using the resin
composition and plastic films according to the examples and
comparative examples, respectively, under the following conditions,
how are the resulting prints were observed.
[0157] Apparatus: product of Nissio Gravure Co., Ltd., bench
gravure printing machine "GRAVO PROOF MINI"
[0158] Gravure cylinder: 60 lines/cm, cell depth: 40 .mu.m
[0159] Process speed: 80 m/minute and 50 m/minute
[0160] The gravure printability was evaluated based on the prints
printed at a high process speed (80 m/minute) and a low process
speed (50 m/minute), respectively, according to the following
criteria:
The print was in exact accordance with the printing plate even at a
high speed (80 m/minute): Good gravure printability
(.smallcircle.); Although grazing occurred at a high speed (80
m/minute), the print was in exact accordance with the printing
cylinder at a low speed (50 m/minute): Usable gravure printability
(.DELTA.); The print was not in accordance with the printing plate
even at a low speed (50 m/minute): Poor gravure printability
(x)
(11) Curability (Initial Tack)
[0161] Immediately after carrying out curing in the examples and
comparative examples, the surfaces of cured layers (coating layers)
were touched by a finger, and whether or not the ink was attached
to the finger was visually observed. A sample was evaluated as
having good curability (.smallcircle.) when the ink was not
attached to the finger; and one was evaluated as having poor
curability (x) when the ink was attached to the finger.
(12) Resistance to Chemicals (Solvent Resistance)
[0162] Surfaces of cured layers (coating layers) were rubbed ten
times in back-and-forth motion with cotton swab impregnated with
methyl ethyl ketone, and the surfaces were visually observed. A
sample was evaluated as having good resistance to chemicals
(.smallcircle.) when the ink was not dissolved. A sample was
evaluated as having poor resistance to chemicals (x) when the ink
was dissolved.
(13) Water Repellency (Measurement of Angle of Contact)
[0163] The angles of contact between water and surfaces of cured
layers (coating layers) of the plastic labels were measured
according to JIS R 3257-6. A sample having an angle of contact of
90 degrees or more was evaluated as having good water repellency
(O), and one having an angle of contact of less than 90 degrees was
evaluated as having poor water repellency (x).
(14) Suitability for Shrinking
[0164] Plastic labels were detached from the labeled containers
prepared according to the examples and comparative examples, and
cured layers (coating layers) in portions which had been attached
to bodies of the containers were observed upon whether or not there
were delamination or crack (large crack) of the ink, whitening
(fine cracking) in the case of a clear coating ink, and transfer
(migration) of the coating layer to the container. The observations
were performed on the labels for ten-containers of each of examples
and comparative examples. The labels for ten-containers showing no
defect such as cracking were evaluated as having good suitability
for shrinking (.smallcircle.), and the label for at least one
container showing any defect such as cracking was evaluated as
having poor suitability for shrinking (x).
[0165] Examples are shown below.
Example 33
[0166] The resin composition (white ink) was prepared by dispersing
and mixing components in a disperser for 30 minutes. The components
were 34 parts by weight of 3-ethyl-3-hydroxymethyloxetane (product
of Toagosei Co., Ltd. under the trade name of "ARON OXETANE
OXT-101") as Component A (A2); 15 parts by weight of
3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexanecarboxylate
(product of Daicel Chemical Industries, Ltd. under the trade name
of "Celloxide 2021") as Component B (B2); 3 parts by weight of a
silicone modified with epoxy at both terminals (product of
Shin-Etsu Chemical Co., Ltd. under the trade name of "X-22-169B":
alicyclic epoxy group, epoxy equivalent: 1700) as Component C
(C14); 3 parts by weight of a photoinitiator (product of Asahi
Denka Kogyo K.K. under the trade name of "ADEKA OPTOMER SP-150"); 1
part by weight of a photosensitizer (product of Nippon Kayaku Co.,
Ltd. under the trade name of "KAYACURE-DETX-S"); 40 parts by weight
of titanium dioxide (product of Ishihara Sangyo Kaisha, Ltd. under
the trade name of "TIPAQUE PF-736") as a white pigment; and 1 part
by weight of silica (product of Tosoh Silica Corporation under the
trade name of "NIPGEL AY-401") and 3 parts by weight of an oxidized
polyethylene wax (product of Mitsui Chemicals, Inc. under the trade
name of "MITSUI HI-WAX 220 MP") as lubricants. No solvent was used
herein.
[0167] The resin composition as an ink was applied to a gravure
cylinder with 60 lines/cm and a cell depth of 40 .mu.m in a bench
gravure printing machine (product of Nissio Gravure Co., Ltd. under
the trade name of "GRAVO PROOF MINI"), the cylinder was rotated
five times to conform the ink therewith. Then, the ink was applied
onto a rectangular piece of a polyester shrink film (product of
Toyobo Co., Ltd. under the trade name of "Spaceclean (S7042)"; film
thickness: 50 .mu.m) through gravure printing at a process speed of
50 m/minute.
[0168] Next, curing with ultraviolet rays was conducted with an
ultraviolet irradiator having an electrode lamp (product of GS
Yuasa Lighting Ltd. under the trade name of "4-kW One-lamp Conveyer
CSOT-40") at a process speed of 30 m/minute, an irradiation
distance of 8 cm, and an output of 3 kW. Thus, a plastic label was
prepared.
[0169] Subsequently, a labeled container was prepared in the
following manner. The plastic label was formed into a round
cylinder so that the printed surface constituted an inner side, the
length in circumferential direction of the cylinder was adjusted so
that the label would be attached to a body of a PET bottle with
thermal shrinkage of 20%, both ends of the label were fused and
adhered with each other to yield a cylindrical plastic label. The
cylindrical plastic label was attached to a 500-ml PET bottle,
subjected to shrinking of the film by immersing in hot water at
90.degree. C. for 20 seconds, and thereby yielded the labeled
container.
[0170] As is shown in Table 5, the resin composition was good in
processability such as gravure printability and curability, and the
plastic label excelled in properties typically in scratch
resistance, resistance to chemicals, and overprintability.
Example 34
[0171] The resin composition, a plastic label, and a labeled
container were prepared by the procedure of Example 33, except for
using a silicone modified with epoxy in its side chain (product of
Shin-Etsu Chemical Co., Ltd. under the trade name of "KF-102";
alicyclic epoxy group, epoxy equivalent: 3600) as Component C (C15)
as shown in Table 5.
[0172] The resin composition was good in processability such as
gravure printability and curability, and the plastic label excelled
in properties such as scratch resistance, resistance to chemicals,
and overprintability as demonstrated in Table 5.
Example 35
[0173] The resin composition, a plastic label, and a labeled
container were prepared by the procedure of Example 33, except for
using a silicone modified with epoxy at both terminals (product of
Shin-Etsu Chemical Co., Ltd. under the trade name of "X-22-163B";
aliphatic epoxy group (glycidyl-type), epoxy equivalent: 1750) as
Component C (C16) as shown in Table 5.
[0174] The resin composition was good in processability such as
gravure printability and curability, and the plastic label excelled
in properties such as scratch resistance, resistance to chemicals,
and overprintability as demonstrated in Table 5.
Example 36
[0175] The resin composition, a plastic label, and a labeled
container were prepared by the procedure of Example 33, except for
changing the amounts of Component A and Component C as shown in
Table 5.
[0176] The resin composition was good in processability such as
gravure printability and curability, and the plastic label excelled
in properties such as scratch resistance, resistance to chemicals,
and overprintability as demonstrated in Table 5.
Example 37
[0177] The resin composition, a plastic label, and a labeled
container were prepared by the procedure of Example 33, except for
changing the amount of Component C as shown in Table 5.
[0178] The resin composition had a high viscosity and was somewhat
inferior in gravure printability at a high speed to that in Example
33, but the plastic label excelled in properties in scratch
resistance, resistance to chemicals, and overprintability, as shown
in Table 5.
Example 38
[0179] The resin composition (clear coating composition) was
prepared by the procedure of Example 33, except for changing the
amounts of Component A and Component B, and for not using titanium
dioxide as shown in Table 5. Then, a plastic label and a labeled
container were prepared by the procedure of Example 33.
[0180] The resin composition was good in processability such as
gravure printability and curability, and the plastic label excelled
in properties such as scratch resistance, resistance to chemicals,
and overprintability as demonstrated in Table 5.
Example 39
[0181] A plastic label and a labeled container were prepared by
using the resin composition prepared according to EXAMPLE 33 and
curing the composition through irradiation with electron beams
instead of ultraviolet rays. The irradiation with electron beams
was carried out in one pass with an electron beam radiator (product
of Iwasaki Electric Co., Ltd. under the trade name of "CB250/30/20
mA") at an acceleration voltage of 150 kV, a beam current of 3.5
mA, a conveyer speed of 20 m/minute, a dose of 15 kGy, and an
oxygen concentration of 500 ppm.
[0182] The resin composition was good in processability such as
gravure printability and curability, and the plastic label excelled
in properties such as scratch resistance, resistance to chemicals,
and overprintability as demonstrated in Table 5.
Example 40
[0183] A plastic label and a labeled container were prepared by the
procedure of Example 33, except for using a polyolefin shrink film
(product of Gunze Packaging Systems Co., Ltd. under the trade name
of "FL2"; film thickness: 50 .mu.m) as a plastic film.
[0184] The resin composition was good in processability such as
gravure printability and curability, and the plastic label excelled
in properties such as scratch resistance, resistance to chemicals,
and overprintability as demonstrated in Table 5.
Comparative Example 10
[0185] The resin composition, a plastic label, and a labeled
container were prepared by the procedure of Example 33, except for
not using Component C and for changing the amount of Component A as
shown in Table 5.
[0186] The cured layer was poor in toughness, resistance to
chemicals, and water repellency, and the plastic label and labeled
container were poor in properties as being susceptible to ink
cracking, and also poor in overprintability as demonstrated in
Table 5.
Comparative Example 11
[0187] The resin composition was prepared by the procedure of
Example 33, except for not using Component B and for changing the
amount of Component A as shown in Table 5.
[0188] As demonstrated in Table 5, a plastic label and a labeled
container were not obtained, because the coating layer in this
comparative example did not sufficiently cure by the application of
ultraviolet rays and showed tackiness.
Comparative Example 12
[0189] The resin composition, a plastic label, and a labeled
container were prepared by the procedure of Example 33, except for
using a regular straight-chain silicone (straight silicone)
(product of Shin-Etsu Chemical Co., Ltd. under the trade name of
"KF-96-50CS") as Component C (C17) instead of the epoxy-modified
silicone.
[0190] The cured layer was poor in toughness and resistance to
chemicals, and the plastic label and labeled container were poor in
properties as being susceptible to ink cracking, and also poor in
overprintability as demonstrated in Table 5.
Comparative Example 13
[0191] The resin composition was prepared by the procedure of
Example 2 in Japanese Unexamined Patent Application Publication
(JP-A) No. H11-140279, using 75 parts by weight of
3-ethyl-3-[(phenoxy)methyl]oxetane (product of Toagosei Co., Ltd.
under the trade name of "ARON OXETANE OXT-211") (A3); 25 parts by
weight of a bisphenol-A epoxy compound (product of Tohto Kasei Co.,
Ltd. under the trade name of "YD-128") (B3); and 2 parts by weight
of a photoinitiator (product of The Dow Chemical Company under the
trade name of "CYRACURE UVI-6992").
[0192] The resin composition had a high viscosity and failed to
yield a coating layer by gravure printing as demonstrated in Table
5.
[0193] [Table 5]
TABLE-US-00005 TABLE 5 Exam- Exam- Exam- Exam- Exam- Exam- Exam-
Exam- Comp. Comp. Comp. Comp. ple 33 ple 34 ple 35 ple 36 ple 37
ple 38 ple 39 ple 40 Ex. 10 Ex. 11 Ex. 12 Ex. 13 Amount Component
A2 34 34 34 36.5 34 65 34 34 37 49 34 A (oxetane A3 compound) 75
Component B2 15 15 15 15 15 24 15 15 15 0 15 B (epoxy B3 compound)
25 Component C14 3 0.5 20 3 3 3 0 3 0 C (epoxy- C15 modified C16 3
silicone) 3 Straight C17 3 silicone Photoinitiator 3 3 3 3 3 3 3 3
3 3 3 2 Sensitizer 1 1 1 1 1 1 1 1 1 1 1 0 Pigment (white) 40 40 40
40 40 0 40 40 40 40 40 0 Lubricant silica 1 1 1 1 1 1 1 1 1 1 1 0
polyethylene 3 3 3 3 3 3 3 3 3 3 3 0 wax Pro- Gravure printability
.largecircle. .largecircle. .largecircle. .largecircle. .DELTA.
.largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. .largecircle. X perty Curability (initial tack)
.largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. X .largecircle. -- Adhesion (tape peeling)
.largecircle. .largecircle. .largecircle. .DELTA. .largecircle.
.largecircle. .largecircle. .largecircle. X -- X -- Crumpling
resistance .largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. -- .largecircle. -- Scratch resistance .largecircle.
.largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. .largecircle. .largecircle. .largecircle. --
.largecircle. -- Resistance to .largecircle. .largecircle.
.largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. .largecircle. .DELTA. -- .DELTA. -- chemicals Water
repellency .largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. .largecircle. .largecircle. .largecircle. X --
.largecircle. -- Suitability for .largecircle. .largecircle.
.largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. .largecircle. X -- X -- shrinkinng Overprintability
.largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. .largecircle. .largecircle. .largecircle. X -- X
--
INDUSTRIAL APPLICABILITY
[0194] The active energy ray-curable resin composition for the
plastic film according to the present invention has low viscosity
and is thereby satisfactorily applied to the plastic film typically
through gravure printing or flexographic printing. The composition
is cured rapidly to attain high productive efficiency of plastic
labels. The composition excels in adhesion to plastic films, and
after curing, it gives a resin layer that satisfactorily follows
the deformation of base film during shrinking process and excels in
scratch resistance and crumpling resistance. In addition, it excels
in resistance to chemicals and in adhesion to another ink
composition (recoatability) if overcoated. Accordingly, the resin
composition according to the present invention is particularly
useful typically as printing inks for the production of plastic
labels. Plastic labels bearing coatings of the resin composition
are particularly useful as labels to be applied typically to glass
bottles, plastic containers such as PET bottles, and metallic
containers such as bottle cans.
* * * * *